JPH0576038A - Auto-white balance device - Google Patents

Abstract

PURPOSE:To exactly correct a white balance by eliminating the influence of a chromatic color by controlling the white balance by using the movement information of a picture. CONSTITUTION:This device is equipped with a movement information extractor 7 which extracts the movement information of the picture, white balance controller 8 which controls the white balance by detecting the color temperature information of the picture, signal processing part 6 which superimposes the white balance on a video signal, and signal output terminal 9. Then, the movement information of the picture is extracted by the extractor 17, and the control of the white balance is operated by judging the panning state of a video camera and the state of an object. Thus, even when the object in the chromatic color such as red or blue is intruded into a screen, it is judged as the intrusion of the object in the chromatic color, and the correct adjustment of the white balance can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic white balance device used for video cameras and the like.

[0002]

2. Description of the Related Art In recent years, as an automatic white balance device used for a video camera or the like, an internal photometric system which has improved performance and does not require an external sensor is becoming mainstream. The basic idea of the internal photometry method is that the subject is an achromatic color on average, that is, the average values of the red, green, and blue color signals will be equal in the screen.

An example of a conventional automatic white balance device will be described below with reference to the drawings. (Figure 7)
FIG. 6 is a structural diagram showing a structure of a conventional auto white balance device.

In FIG. 7, 1 is a CCD, 2 is a signal processor, 3 is a white balance controller, and 4 is a video signal output terminal.

Light incident on the CCD 1 is photoelectrically converted by the CCD 1 into a video signal, which is sent to the signal processing unit 2. In the white balance controller 3, first, the integrated value ΣR of the R signal, the integrated value ΣB of the B signal and the integrated value ΣG of the G signal of the entire screen are input from the signal processing unit 2. Next, the white balance controller 3 determines the amplification factors of the amplifiers for the R signal and the B signal in the signal processing unit 2 from ΣR, ΣB, and ΣG and sends them to the signal processing unit 2. The amplification factors of the R signal and B signal amplifiers are given by ΣG / ΣR and ΣG / ΣB, respectively. As a result, the ratio of the average values of the R, G, and B signals of the output signals on the entire screen becomes 1: 1: 1, and a white-balanced output signal is obtained from the output terminal 4.

[0006]

However, in the above-mentioned configuration, when a red or blue chromatic color subject enters the screen, the ratios of R, G and B of the entire screen are made equal. Therefore, there is a problem in that an erroneous operation, such as correcting the white balance so as to dilute the color of the chromatic subject, may occur.

In view of the above points, it is an object of the present invention to provide an automatic white balance device capable of accurately correcting white balance without being affected by chromatic colors.

[0008]

To achieve the above object, the present invention provides a motion information extractor for extracting motion information of an image and a white balance control for detecting color temperature information of the image and controlling white balance. And a signal processing unit that applies white balance to the video signal, and performs white balance control using image motion information.

[0009]

According to the present invention, the motion information of the image is extracted by the motion information extractor, and the panning condition of the video camera and the condition of the subject are determined to control the white balance in the screen. Even if a red or blue chromatic subject has entered, it can be determined that a chromatic subject has entered, and the white balance can be properly adjusted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic white balance device according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a structural diagram showing the structure of an automatic white balance device according to an embodiment of the present invention. FIG. 2 is a flowchart showing an algorithm of the automatic white balance device according to the embodiment of the present invention. FIG. 3 is a diagram showing a motion detection operation of the automatic white balance device according to the embodiment of the present invention. (FIG. 4), (FIG. 5), and (FIG. 6) are diagrams for explaining the operation of the automatic white balance device according to the embodiment of the present invention.

In FIG. 1, 5 is a video camera (not shown).
CCD built in the image pickup device such as, 6 is a signal processing unit, 7
Is a motion information extractor, 8 is a white balance controller, and 9 is a signal output terminal.

The signal photoelectrically converted by the CCD 5 is input to the signal processing unit 6. In the motion information extractor 7, the signal processing unit 6
The image signal of 1 field is input and the image signal of the previous field is compared with the image signal of the current field to obtain the direction and amount (motion vector) of the motion. The motion vector is detected in four zones of one screen as shown in (FIG. 3). The original purpose of the motion information extractor 7 is to correct the camera shake of the video camera. The motion information extractor 7 uses fuzzy theory to determine whether the motion vector obtained next is due to camera shake or motion of the subject. The rule of the fuzzy theory is that if different motion vectors are detected and the difference is large, it is judged as a moving subject, and if all the motion vectors are in the same direction and the difference is small, it is judged as a camera shake condition. Is to do.

As an example of the motion discrimination of the fuzzy theory,
When the four motion vectors point in the same direction as shown in FIG. 4, it is determined that the motion blur is caused, and the motion blur correction is performed. If the amount of the motion vector is larger than a certain level as shown in (FIG. 5), it is determined that the panning is not the camera shake and the camera shake correction is not performed. Further, as shown in (FIG. 6), when one or two of the four motion vectors point in different directions, it is fuzzy determined from the relationship between the amount and size of each motion vector and the image stabilization is controlled. It

As shown in FIG. 3 for correcting camera shake,
In accordance with this motion vector, the cutout frame of the screen output from the field memory in the signal processing unit 6 is translated in the direction opposite to the motion to correct the shake. As a result, the signal processing unit 6 obtains a still image.

Next, the white balance controller 8 controls the white balance according to the algorithm shown in FIG.

First, the color temperature of the current video signal is detected from the video signal of the signal processing unit 6 (101). To detect the color temperature, the integrated value ΣR of the R signal and the integrated value ΣB of the B signal of the entire screen are extracted from the signal processing unit 6, and the ratio ΣB / ΣR is calculated.
Can be obtained at.

Next, for the control of the white balance, the currently set color temperature is compared with the detected color temperature (10).
2). If the color temperature has not changed, it is not necessary to correct the color temperature, and the process returns to the first step.

If the color temperature has changed, the motion information extractor 7 detects motion information indicating whether or not the camera shake correction is performed (103). When the motion information extractor 7 is performing the camera shake correction, the image is in a static state, so that the color temperature does not change and it is not necessary to correct the color temperature.

When the image stabilization is not performed, the image is in the panning state or the zooming state, so the color temperature is corrected (104). To correct the color temperature, the integrated value ΣG of the G signal of the entire screen is extracted in the same manner as ΣR and ΣB, and the signal processing unit 6 calculates ΣG / ΣR and ΣG / Σ for the R signal and the B signal.
When the gain of B is multiplied, the ratio of the average value of the R, G, and B signals of the output signal on the entire screen becomes 1: 1: 1, and a white-balanced output signal is obtained from the output terminal 9. After the color temperature correction, the color temperature set at that time is stored in the memory (105).

As described above, according to this embodiment, the motion information of the image is extracted by the motion information extractor 7, and the panning condition of the video camera and the condition of the subject are judged to control the white balance. Even if a chromatic subject such as red or blue has entered the screen, it can be determined that a chromatic subject has entered, and the white balance can be properly adjusted.

[0021]

As described above, according to the present invention, it is determined from the motion information of the video signal whether the video camera is panning or stationary, and the white balance is controlled only during panning. As a result, even if a red or blue chromatic color subject has entered the screen where the video camera is stationary, it can be determined that a chromatic color subject has entered, and the white balance can be properly adjusted.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an automatic white balance device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an algorithm of the automatic white balance device.

FIG. 3 is a diagram showing a motion detection operation of the same automatic white balance device.

FIG. 4 is a diagram for explaining the operation of the automatic white balance device.

FIG. 5 is a view for explaining the operation of the automatic white balance device.

FIG. 6 is a view for explaining the operation of the automatic white balance device.

FIG. 7 is a block diagram of a conventional auto white balance device.

[Explanation of symbols]

 5 CCD 6 signal processor 7 motion information extractor 8 white balance controller 9 video signal output terminal

Claims (2)

[Claims] 1. A motion information extractor for extracting motion information of an image, a white balance controller for detecting color temperature information of the image to control white balance, and a white balance for a video signal obtained from the image. An automatic white balance device, comprising: a signal processing unit for controlling the white balance, using the motion information of the image. 2. A motion information extractor that extracts motion information of an image, a white balance controller that detects color temperature information of the image and controls white balance, and a video image obtained from the image through an imaging device. A white balance control unit that applies a white balance to a signal, holds the white balance control state when the image pickup apparatus is in a stationary state, and controls the white balance in other states. Balance device.